Method of preparing lithographic stones.



H. BUSGH & W. SGHUPBAGH.

METHOD or PREPARING LITHOGRAPHIG STONES.

APPLICATION FILED MAIL. 9, 1914.

Patented Aug. 25, 1914.

THE NORRIS PETERS CO.. PHOTO-LITHO.. WASHINGTON, D. C.

:i TED STATES PATENT OFFIQ.

' HENRY BUSCH AND WALTER SGI-IUPBACH, OF NEW YORK, N. Y.

METHOD OF PREPARING LITHOGRAPHIC STONES.

Specification of Letters Patent. -Patente(l Aug. 25, 1914:.

Application filed March 9, 1914- Serial No. 823,534.

To all whom it may concern:

Be it known that we, HENRY Russia, a

citizen of the United States, and a resident of the city of New York, lVoodhaven, borough of Queens, in the county of Queens and State of New York, and VALTER Sonor- BAGI-I, a citizen of the United States, and a resident of the city of New York, borough of Manhattan, in the county and State of New York, have invented a new and Improved Method of Preparing Lithographic Stones, of which the following is a full, clear, and exact description. Among the principal objects which the present invention has in view are: to provide means for registering a tinting screen of'the Ben Day type upon successive stones em,- ployed in lithography; to provide means for avoiding the production of .patterns when using a tinting screen in lithography; and to reduce the expert-labor factor in preparing stones for lithographic printing.

Figure l is a view of a protractor card used in the present method, and constructed and arranged in accordance with the present invention; Figs. 2, 3, 4L and 5 are diagrammatic views showing stones prepared in accordance with the present invention, preparatory to receiving the tinting rule thereon; Fig. 6 is a faceview of a tinting screen commonly known as Ben Day medium; Fig. 7 is a back view of the same, having imparted thereto a registeringmember arranged in accordance with the present invention.

hen employing the tinting screen 12, said screen is held in a supporting frame, not shown in the accompanying drawings. Said supporting frame employs a shifting mechanism, the operation whereof shifts or moves the screen 12 in a definite line, the amount of movement being determined by the operator. The face 13 of the screen is molded or otherwise provided with regularly-disposed, minute protrusions or papilla-like extensions.

In the employment of the screen, the surface 13 is supplied with ink, which is thereafter removed from the higher points or face of the screen,much in the same manner as the surplus ink is removed from a hand printing pad. The screen is thereafter laid or superposed on a stone, and the ink is transferred to the surface of the stone by the operator, with a stylus or hand rubbing on the back of the screen to press the ink upon the stone, to transfer said ink to the surface of the stone.

The screen is constructed preferably from a-transparent material, by means of which the operator may view the ofiset 1a with which each of the stones is provided. In this manner, the operator sees the area over which the color is tobe laid for which he is at that time preparing the stone. .The

screen 12' is shifted by the operator, in line with the direction in which he rubs, as in well known practice. The screen, when shifted, forms a series of ink spots so closely connected as to form a series of parallel tinting lines of ink or medium, which thereafter hold or carry the colored ink used in lithographic printing. It depends upon the arrangement of the tinting lines thus imparted to the stone, whether the lines of the various colored tints shall form an even tone, or run to what are known in the art as patterns. It is the desire of the operator to dispose the lines of tinting onthe various stones in relative angles evenly spaced or protracted in regular angular relation. Thus, if two stones are to be tinted for what is styled two-color work, the lines of the tint on the stone should be disposed at 80 relatively each to the other. If a third color is tobe employed, the-lines of tint should clearly bisect the remaining angle of forming a new relation of 30". If a fourth color is employed, the division of the 90 should be in three equal divisions, the angular relation then being 30 each to the other, the last lines being perpendicular to the frst line. If a fifth color is employed, lines perpendicular to the second lines of the first series above mentioned are laid. If a sixth color is to be provided for, the lines would be perpendicular to the third of the series of lines above referred to. In other words, all of the lines for the tinting will have a regular angular relation, the angle being preferably 30, this disposition having been found to be that which most surely avoids the formation of the objectionable-pattern above referred to. Tinting, if perfectly performed as indicated, will produce an even tone in the completed lithograph. It will be understood that the accuracy thus indicated calls into play a large factor of skill and time.

In the present invention, the protractor 15 is constructed from transparent material,

such as celluloid, and is engraved with a mentary values. One of the lines, and preferably as shown in the drawingsthe line designated by the name Black, corresponds with a direction line 16, which is formed on the back of the screen 12. The line 16 accurately coincides with the angular relation of the papilla on the face 13 of said screen. All rubbing which is performed on the face of the screen, when following the herein-disclosed method, is parallel with the direction line 16, and all movement of the screen is likewise parallel with saiddirection line 16. When thus provided with a protractor 15 and a screen 12 having a direction line 16 thereon, the stones 17 18, 19 and 20 are tinted as follows: In the first instance, the protractor is employed by the artist to indicate the color offsets for the guidance of the tinter. The offsets 14 are placed on the various stones, the offset areas being indicated with reference to the color for which the stone is selected. Thus, in Fig. 2, the stone has been selected for tinting to receive black ink, and the line indicated as Black has been impressed thereon, the protractor 15 being usedfor this purpose. The stone 18 has been selected for a blue color, and the tinting line has been impressed thereon to indicate the blue. A similar selection for the sto-ne19 and a marking to show that the yellow color is to be carried thereby, is indicated the line marked Yellow, and in a similar way, the line marked Red has been imprinted on the stone 20. All of these lines bear a definite relation to the line marked Black on the stones and transfers 14, to register or key with said transfers and some master point thereon. When the stones thus prepared are delivered to the operator, the screen 12 is adjusted in each instance with the face 13 thereof turned to the stone, and the direction line 16 disposed in parallel relation to the color line with which the stone is to be impressed. Thus, if the stone is to be tinted for black, the Black line alone would show. If the stone is to be tinted for yellow, the Black? and the Yellow would show. This would indicate, however, to the operator that the Yellow line was to be followed by him, the Black line only having been originally impressed to obtain the proper registration for the Yellow line. In each instance, the screen is preferably rubbed, as indicated above, in a direction parallel with the line 16. When the screen is transparent, the offsets or areas tobe tinted show therethrough, and the rubbing may be limited to these areas only. At the end of the operation, it will be found that a number of offsetareas have been ruled or tinted, the lines of which bear accurate angular relation each to the other. As a result of the even, angular relation of the lines of tinting, the lithograph resulting from the printing of the various stones will be even in tone, and have none of the ob ectionablepattern above re ferred to. s It 1s obvious that,hav1ng stones thus prepared, the skill required of the op-' erator, in the tinting of the stones, is materially less than that required by the old method, and that the direction lines for the rubbing or line arrangement of the tints being indicated on the stones, the time factor in the operation of tinting the stones is materially diminished.

Claims:

1. A method as characterized, consisting in providing a series of stones with offset transfers; then providing said stones with color markings to indicate the desired direction of the tinting lines for said stones; and then superposing a tinting screen on said stones, said screen having a direction line thereon for registry thereof with the marks on said stones.

2. Amethod as characterized, consisting in providing a series of stones with offset transfers; then providing said stones with color markings to indicate the desired direction of the tinting lines for said stones; and then providing a tint on said stones in conformity with the color markings thereon.

3. A method. as characterized, consisting in providing a series of stones with offset transfers; then providing said stones with color markings to indicate the desired direction of the tinting lines for said stones; and then registering a tintingscre'en with the color markings on said stones; and then manipulating said screen to produce par allel tinting lines in ofiset areas on said stones.

4. A method as characterized, consisting I s in providing a series of stones with a series of offset transfers; then marking on said stones indicating lines for showing the direction of the tinting lines desired for the particular offset; then marking a tinting screen with a direction line coinciding with the line of movement of said screen and the direction for manipulating the same; then superposing said screen and registering the direction mark thereon with the indicating marks on said stones; and then rubbing and shifting said screen to form tinting lines on the stones coincident with the offset areas.

5. A method of forming line tinting areas on lithographic stones for the product ion of two and three color work, consisting in providing a series of stones with offset transfers and providing said stones with markings to indicate the desired direction of the tinting lines for said stones, said markings being mutually related to form angles of 30 degrees; then providing a tinting screen with registering marks, wherewith to place said screen on each of said stones to form tinting lines in parallel relation to the markings thereon.

6. A method of tinting lithographic stones for poly-chromatic work, consisting in marking the stones in series of three and less than three, the markings on the successive stones being set relatively at angles of 80 degrees, the tinting lines of the second series being relatively perpendicular to the lines similarly, serially related in the first series; and then imparting to the said stones by means of a suitable tinting screen, lines 20 parallel to said markings.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

HENRY BUSCH. Witnesses:

CHAs. E. BIETH, JOHN SUEHOFF. In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

WALTER SCHUPBACH.

Witnesses:

WM. C. AYMAR, WM. A. ROBERTS.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner or Patents.

Washington, D. 0. 

